Considering the Atlantean temple was full of death traps, it seems weird how easy it was for Glomgold to take the Jewel of Atlantis. This makes it an early clue to the fact that Glomgold didn't take the real Jewel of Atlantis.
Glomgold's henchmen are quickly defeated by three kids and a delirious Launchpad. Early in the episode, Glomgold called his henchmen "the best of the cheapest"; in other words, he got what he paid for.
Mrs. Beakley and Donald Duck get along splendidly; they're single parents, or grandparents, raising young children, and are overprotective. He also knows her personally, probably having gotten into quite a few scrapes with his back when he still went adventuring with Scrooge.
The incident that got Della Duck out of the picture is called "Spear of Selene". Selene is the Greek word for "moon", and Della Duck is an astronaut in the comics...
Also, what’s the most famous level in the DuckTales game? The Moon.
Meta, but Launchpad knowing Swedish makes sense. Back in the early cartoon, pretty much everyone spoke English (including lost tribes and other people who would be unlikely to be fluent.) This is something that wouldn't fly now. English is the language of business so Scrooge may know some other languages but either common ones or just business terms. Launchpad is a Genius Ditz who probably interacts with the drivers of foreign businessducks and others who may not be fluent (or expected to be fluent) in English, so of course he picks up the more obscure ones!
As for why the pronunciation is so off? Well, would you be able to talk correctly after getting injected with so much Snake Venom?
Additionally, it's Swedish because Duck comics are so popular in Scandinavia. Which may be a better explanation since Swedes would be expected to be fluent in English.
Scrooge tells Beakley that family is "nothing but trouble"; when he later tells Huey, Dewey, Louie & Webby that they are "nothing but trouble", he adds on how he’s “missed trouble”; Scrooge McDuck misses being part of a family!?
When riding the gold hunting dragon, Scrooge exclaims that it takes more than just a bumpy flight to shake him off. Of course he would say that, he's used to Launchpad's bad driving.
And then you learn in later episodes the sort of muscles and dexterity he had to build up in order to be able to swim through piles of gold coins, which explains how he was able to shake off being smacked into several buildings by said dragon.
You'd expect that Beakley would be furious with her granddaughter for lying to her about a dangerous venture. But she realized that Webby was with Scrooge when Launchpad answered the phone, posing as "Uncle Hampus"; she's known Launchpad for years and would recognize his voice, especially when speaking a foreign language. So she figures out where Webby is — with Scrooge and Launchpad— and knows that she's safe.
In fact, Beakley said she knew Webby was lying the whole time. And why not? After all, Scrooge already told her he was taking the "wee ones" on a field trip, after he'd already discussed a trek to Atlantis with her. What's more, Webby called her from Scrooge's phone. Assuming the phones in McDuck Manor, or even Mrs. B's phone, have caller I.D., she knew who Webby was with the whole time. Plus, let's face it, as Louie pointed out, they were pretty awkward, transparent lies. After all, Webby has already been established as a Socially Awkward Hero, and the triplets are almost certainly her only friends, which throws the first lie (that she's spending the night at a friend's house) right out the window, and it's all downhill from there, especially since Launchpad referred to her by name.
Even easier answer. She said she was spending the night with friends. Webby doesn't have any friends except the nephews.
In a Freeze-Frame Bonus, when Scrooge is sitting across the dining room table from his great nephews, there's a large portrait on the wall behind them of 2 older ducks. Well, if you look at Webby's chart, it's made clear that those 2 are in fact Scrooge's parents. The framing of that shot is to show that Scrooge is having family and love pushed into his life again.
Glomgold refers to himself as "The World's Most Beloved Scottish Billionaire Duck." While it's a blatant lie that Glomgold is more popular than McDuck, this is actually a true statement: Scrooge can't be the most beloved Billionaire because he's established when Donald drops the triplets off as a Trillionaire, leaving the "most beloved Scottish billionaire duck" title to fall to Glomgold, the second richest duck in the world.
The examples of Scrooge's adventures that the nephews bring up when discussing how cool he is in the first episode each reflect their personalities:
Huey — the nerdy, intellectual bookworm — discusses Scrooge using his intelligence to solve a mystery and unmask the chupacabra.
Dewey — the impulsive, glory-seeking adventure junkie — recounts a fight that Scrooge got into with a rock monster and how he then created a statue to himself out of the defeated monster's remains.
Louie — the materialistic Gold Digger — describes Scrooge enjoying his enormous wealth by swimming in it.
Similarly, each of the nephews reflects an aspect of Scrooge's own personality:
Huey is his intelligent, mystery-solving side.
Dewey is his adventurous, reckless side.
Louie is his cunning, greedy side.
They also have a negative quality that offsets the positives. Huey is intelligent, but too strict with the rules. Dewey is adventurous, but too fool-hardy. Louie is clever, but too lazy to implement that intelligence. They all need the influence of a successful businessman/adventurer like Scrooge to mentor them.
Donald, as hyperprotective as he is, allows Huey to be a Junior Woodchuck, a rather adventurous group of scouts. Either he doesn't know how adventurous they are, or he knows just how Crazy-Prepared they are (seriously, it describes how to capture a sasquatch and even how to knock it out!) and trusts their preparation-and the more experienced troop leaders in case the preparation for once isn't enough.
When Donald is showing his new workmates pictures of his nephews, we see one of little Dewey's first steps, then Huey at the play-offs (as the water boy)... then a whole family photo rather than one of Louie specifically. Why is that? Because Louie is both The Baby of the Bunch and Brilliant, but Lazy. By the time he hit his first milestones (like learning how to walk) Huey and Dewey had probably already done it (if for no other reason than they're more ambitious), and he'd never apply himself to things like join sports or junior scouts. The only (noteworthy) pictures Donald would have involving Louie would probably be ones where he was dragged along with the family, like going to the grocery store.
The snakes falling on Launchpad is amusing, and plays into later jokes, but it doesn't make much sense as a trap—until you remember Atlantis is inverted. What Dewey triggered is a fairly common pit trap full of snakes, but because it is upside down, the snakes fall out.
Scrooge's Money Bin being located out in the water:
The water gives it natural defenses in the form of water currents, similar to Alcatraz, compared to the Money Bin of the comics and original cartoon, whose location on top of a hill was exploited repeatedly. It's also a smarter move as Scrooge wouldn't need to maintain the grounds, guards, or the fence. It still does have a major aerial weakness, which is shown off in the very first episode and will likely be exploited by villains in future episodes.
The Bin being out on the water still has the same symbolism as being on a hill, showing Scrooge's wealth and power over Duckburg to anyone who can see the water. A similar comparison can be made between the statues of Christ the Redeemer in Rio de Janeiro and the Statue of Liberty in New York City.
While most of Scrooge's past adventures were at least partially motivated by self-interest, he's still a massive force for good in the world. Naturally the Board of Directors want to keep him at home, sulking in his mansion, instead of being out and about; they're F.O.W.L., and keeping Scrooge neutralized is an organizational priority.
Even ignoring revelations madelater in the series, it makes sense Scrooge's Board of Director's would cut funding into adventuring R&D. As is shown at the end of this episode, Scrooge's adventures either add additional revenue to his company or help cut costs, basically funding the research itself, and since he has not gone an adventure in years, there is no money coming in from Scrooge himself, leading to the funding cut.
It make sense why they would keep adventuring R&D going despite their cutting of funding. The tech made could be sold off or used for non-Scrooge McDuck Industries operations. Or for F.O.W.L. operatives to use.
Donald's My Beloved Smother nature makes the boys more likely to rebel, to the point that they sent away their babysitter and planned to hotwire the boat.
The elderly babysitter being misdirected by the triplets ending up being stranded in the middle of nowhere, with no apparent transportation to bring her back to Duckburg. Thankfully, she has a phone on her.
It's a good thing nobody was in the boat-house when it exploded. Which it could have in Cape Suzette if the boys had made their getaway.
Although if they had been, they'd have presumably remembered to switch the engine off, which was the reason the boat exploded in the first place.
Although Dewey claimed the blame for leaving the engine running, that would have fallen to overprotective, safety-conscious Donald. Why did it happen anyway? Donald was distracted on multiple axes, one alone enough to let him miss that he hadn't properly cut the engine:
Realizing the boys would definitely get in trouble without supervision.
Although he doesn't go abusive with it, Donald's famous temper likely went off like a Roman Candle at discovering Dewey was hotwiring the boat. The shot of the triplets tumbling into the back seat implies it.
Coming to the conclusion that Scrooge was his last resort. He probably can't call Mickey, who is often away on his own adventures and may have his own nephews visiting, and, depending on where the continuity lines up, he might not be willing to trust Goofy with his nephews/Spoonerville isn't close/Goofy has his own kid to look after.
Worry at being late for his interview for a job he really needed to give the boys some stability.
Donald's also right in calling out Scrooge on taking the kids out on an adventure that nearly got them killed. And yet now he has to let them spend time together, since they'll all be living in Scrooge's manor.
Even more horrifying, there's the Spear Of Selene incident, which is implied to be when they broke apart, after Della Duck, Donald's sister and the triplets' mother, disappeared, presumed dead.
Donald describes the flooding treasure room with Dewey trapped inside as a repeat of the Spear of Selene Incident. He was likely visualizing being Forced to Watch his nephew and uncle drown in front of him, all because Scrooge and the boys wanted a grand adventure. This might have happened with Della, and Donald is having Survivor's Guilt about seeing his sister die. To add to the horror, Donald's bad luck ought to have killed him, but it spared him during the Spear of Selene. It could certainly explain why Donald doesn't bother to free himself from the hole in the wall when he realizes despite his best efforts that the room will flood; he may be thinking he's joining his sister and her son in the afterlife.
Donald didn't want to free himself from the trap, his reason being he didn't want to watch Dewey die in front of him. Given his situation (the room was going to fill with water anyways) it could mean that he likely wanted to die first, most likely due to whatever trauma the Spear of Selene incident caused him.
Della took the Spear of Selene, and for that reason Scrooge made her an Unperson. No one talks about her, not even Donald. What was the Spear of Selene and why did Della take it?!
During the Atlantis trip, Dewey could walk across the bridge with the laser trap. But Atlantis is upside down, meaning he was walking on the bottom of the bridge. If the laser-grid/fire trap was on the bottom, makes you wonder what was on the top...
It's a rope/suspension bridge that sags in the middle, so presumably when it was the right way up, it sagged in the other direction and the lasers were still above it.
Also, it was an ancient, crumbling, upside-down suspension bridge. If the death traps weren't dangerous, the bridge itself could have collapsed at any second!
Why is Scrooge so insistent that "family is nothing but trouble"? It's a distancing technique. Put together with how touchy he is over the Spear of Selene and the fact that he'd retired from adventuring for a decade after that event, and it becomes obvious. He loves his family very much and even if the Selene incident wasn't his fault, he's suffering Survivor's Guilt over the loss of Della, and perhaps ordinary guilt over Donald cutting ties with him because of it. He's been lonely but fear over letting them close only to lose them again causes him to insist that he's better off on his own.
Rattlesnakes are among the venomous snake species, though normally they're not aggressive enough to attack people (they'll give you a warning first and be more than happy if you back off), or ducks in this case. Launchpad is pretty lucky he was able to walk off all those bites...
) and trusts their preparation-and the more experienced troop leaders in case the preparation for once isn't enough.